One of those cases involved a DUI investigation last year along a busy stretch in Renton. Prosecutors say the suspect, 20-year-old Emily Falkenstein, was driving along Union Ave. NE while Gregory Ramirez crossed the street in his wheelchair.
Police say Falkenstein hit him in the crosswalk and broke his leg, and when Falkenstein got out of her car, eventually police did a blood draw.
However, even though court records show Falkenstein's blood alcohol level came back at .098 -- over the legal limit of .08 -- and positive for marijuana, prosecutors didn't use that evidence against her.
King County prosecutor Amy Freedheim says they decided to instead charge her with a lesser crime because of a recent U.S. Supreme Court case, which says it's now illegal to draw blood in certain DUI cases without a search warrant. The supreme court says police can draw a suspect's blood without a warrant in a case of an emergency. However, the court did not define what constitutes an emergency.
"As long as we have to put a needle in somebody's arm, that is a more intrusive search," Freedheim said.
The decision is now jeopardizing hundreds of DUI cases across the state, including, possibly, the DUI case against Mark Mullan who is accused of hitting four family members crossing the street on NE 75th Street in Seattle back in March.
The crash killed Dennis and Judith Schulte. Prosecutors say there are serious questions about whether Mullan's blood draw will hold-up in court.
Sgt. Cindi West with the King County Sheriff's Office says the new decision could also hurt countless future cases too, when officers pull-over a DUI suspect in the middle of the night.
"We have to write up a search warrant and call a judge and in some cases that's difficult," West said. "And every minute that ticks by, that evidence goes away."
In the case of Falkenstein, prosecutors say not all is lost. While the 20-year-old didn't serve jail time, she'll still serve 5 years probation.